300 years of Liverpool history show themselves on its modern map [audio 29min]

Archaeologist Julian Richards explores the hidden history of British towns through the streets and buildings of today. In Liverpool -- the Gateway to the Empire -- human traffic through the port created a unique test-bed for new ideas about charity, health provision and disease control. But how does the bustling cosmopolitan history of the last 300 years show itself in the architecture of the city and the shape of the modern map?